> ## Documentation Index
> Fetch the complete documentation index at: https://docs.osis.co/llms.txt
> Use this file to discover all available pages before exploring further.

# What is Comms?

> A real phone line, an inbox, and a Messages API you call from your backend — SMS and iMessage without building the plumbing.

Comms is the messaging layer for your product. You get a line on SMS and iMessage, a human inbox for handoff, and a **Messages API** that works like any other HTTP API you already know.

Use Comms when you need to:

* **Text customers from your backend** — confirmations, reminders, support, ops alerts.
* **Receive replies** — poll the API or get webhooks when messages land.
* **Optionally run agents** — put a no-code agent on the same line without changing how your API key works.

The key you mint is for **using the line from code**. It is not for controlling billing, team, or dashboard settings. AI models will hang off the same key later.

## Choose a path

<CardGroup cols={2}>
  <Card title="Quickstart" icon="rocket" href="/quickstart">
    Mint a key, set `COMMS_API_KEY`, and send your first message in under a minute.
  </Card>

  <Card title="Send your first message" icon="message-square" href="/guides/send-your-first-message">
    Walk through request body, idempotency, and how delivery works on the wire.
  </Card>

  <Card title="API reference" icon="code" href="/messages-api/overview">
    Base URL, auth, scopes, and every endpoint with request and response shapes.
  </Card>

  <Card title="Webhooks" icon="webhook" href="/guides/webhooks">
    Get push events when messages are sent or received instead of polling.
  </Card>
</CardGroup>

## How it fits together

```mermaid theme={null}
flowchart LR
  Backend["Your backend"] -->|"Bearer key"| MessagesAPI["Messages API"]
  MessagesAPI --> Line["Your line"]
  Line --> Customer["Customer phone"]
  Customer --> Line
  Line --> MessagesAPI
  MessagesAPI -->|"optional webhook"| Backend
  Agents["Agents · optional"] -.-> Line
```

| Layer            | What it is                                        |
| ---------------- | ------------------------------------------------- |
| **Your code**    | Server, worker, or script holding `COMMS_API_KEY` |
| **Messages API** | `https://osis.co/api/v1/comms/*`                  |
| **Line**         | SMS / iMessage identity customers text            |
| **Inbox**        | Where your team takes over in the dashboard       |
| **Agents**       | Optional no-code automation on the same line      |

## What this key is not

<Warning>
  Keep Messages API keys **server-side only**. Never ship them in browser code, mobile apps, or public repos.
</Warning>

* Not a dashboard session or admin token.
* Not required for the no-code agent builder.
* Not scoped to “control the platform” — only to send, read, and optionally manage webhooks on the line.

## Next steps

1. [Quickstart](/quickstart) — create a key and land a 202.
2. [Authentication](/messages-api/authentication) — scopes and rate limits.
3. [Send a message](/messages-api/send-message) — full request reference.